Sun Unleashes Largest Solar Flare in Years

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An extremely powerful solar flare, the largest in over four
years, rocked the sun early Tuesday (Aug. 9), but is unlikely to
wreak any serious havoc here on Earth, scientists say.

"It was a big flare," said Joe Kunches, a space scientist with
the National Oceanic and Atmospheric Administration (NOAA)'s
Space Weather Prediction Center. "We lucked out because the site
of the eruption at the
sun was not facing the Earth, so we will probably feel no ill
effects."

Today's solar flare began at 3:48 a.m. EDT (0748 GMT), and was
rated a class X6.9 on the three-class scale scientists use to
measure the strength of solar flares. The strongest type of solar
eruption is class X, while class C represents the weakest and
class M flares are medium-strength events. [ Video:
Aug. 9 Solar Flare Briefly Knocks Out HF Radio ]

The flare is the largest one yet in the sun's current cycle,
which began in 2008 and is expected to last until around 2020.
Solar activity waxes and wanes over an
11-year sun weather cycle, with the star currently heading
toward a solar maximum in 2013.

"This flare had a GOES X-ray magnitude of X6.9, meaning it was
more than 3 times larger than the previous largest flare of this
solar cycle - the X2.2 that occurred on Feb 15, 2011," scientists
with NASA's Solar Dynamics Observatory, a space observatory that
monitors the sun, wrote in an update.

Before the Feb. 15 storm, the largest recent solar flare occurred
in December 2006, when an X9-class solar storm erupted from the
sun.

Solar flares occur when magnetic field lines on the sun get
tangled up into knots, building potential energy until they reach
a tipping point. Then, that energy is converted into heat, light
and the motion of charged particles.

While all X-class
solar eruptions are major events, they pose the greatest
threat to Earth when they are aimed directly at the planet.
During those events the sun often releases a cloud of plasma
called a coronal mass ejection into space, and sometimes toward
Earth. This ejection hurls charged particles that can damage
satellites, endanger astronauts in orbit, and interfere with
power systems, communications and other infrastructure on the
planet.

"Because of its position the CME is going to shoot out into space
and not be Earth-directed, and we don’t expect any big
geomagnetic storm with this," Kunches told SPACE.com. "We did
luck out. If this would have happened a week ago, who knows?"

However, some VLF and HF radio communications blackouts have been
reported, according to Spaceweather.com, a website
that monitors space weather events.

Whatever particles do head our way should reach us in a few days.

"The cloud will probably miss Earth," SpaceWeather.com wrote. "At
this time, however, we cannot rule out a glancing blow from the
flank of the CME on or about August 11th."

The plus side of such a collision is often
unusually spectacular auroras, or Northern and Southern
Lights, which occur when charged particles interact with Earth's
magnetic field.